1. Field of the Invention
The present invention relates to a coil for cordless charging and a cordless charging apparatus using the same, and more particularly, to a coil for cordless charging, which may be formed as a thin coil in spite of the presence of a plurality of coils included therein, and a cordless charging apparatus using the same.
2. Description of the Related Art
In general, portable electronic devices such as mobile communications terminals, personal digital assistants (PDAs), and the like, include a rechargeable secondary battery.
In order to charge a battery of a portable electronic device, a charging apparatus is required to provide electrical energy to the battery by using commercially available household power.
In general, a charging apparatus and a battery have a contact terminal, respectively, and when the two contact terminals thereof are connected, the charging apparatus and the battery are electrically connected.
In this case, however, if the contact terminal is protruded outwardly, an appearance thereof may not be aesthetically pleasing, and the contact terminal may be contaminated by a foreign material to degrade a contact state. Also, when the battery is short-circuited or exposed to moisture due to inadvertent user actions, charged energy may be easily lost.
As an alternative to the contact type charging method, a cordless charging apparatus (or a contactless power transmission apparatus) transmitting power to charge a battery in such a manner that contact terminals of the cordless charging apparatus and the battery are not in contact has been proposed.
In general, a cordless charging apparatus refers to apparatus transmitting power to a contactless power reception apparatus (e.g., a portable device) having a battery, cordlessly.
Such a cordless charging apparatus transmits power by using electromagnetic induction, and to this end, a coil is provided therein.
However, in a related art cordless charging apparatus, connection portions connecting the coil and a driving circuit are formed by soldering. Thus, the related art coil has a thickness disadvantageously increased by as much as a solder ball formed due to soldering.
In line with the recent tendency for ultra-thin electronic devices, an increase in thickness due to a solder ball has emerged as a problem to be tackled and, as a solution, a coil structure for cordless charging is required.